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The present work describes the antinociceptive properties and chemical composition of the aerial parts of Plinia glomerata (Myrtaceae). Both of the extracts evaluated, acetonic and methanolic, showed potent antinociceptive action, when analyzed against acetic acid-induced abdominal constrictions in mice, with calculated ID 50 (mg/kg, i. p.) values of 24.8 and 3.3, respectively. Through usual chromatographic techniques with an acetonic extract, the following compounds were obtained: 3,4,3Ј-trimethoxy flavellagic acid (1), 3,4,3Ј-trimethoxy flavellagic acid 4Ј-O-glucoside (3) and quercitrin (4), which were identified based on spectroscopic data. Compounds 1 (ID 50 = 3.9 mg/kg, i. p., or 10.8 μmol/kg) and 3 (ID 50 = 1.3 mg/kg or 2.5 μmol/kg) were notably more active than some well-known analgesic drugs used here for comparison.

The present study describes the analgesic activity of extracts and some fractions obtained from Erythrina crista-galli leaves in different in vivo analgesic models, using mice as experimental animals. The results showed that extract E(2) was the most active, inhibiting 48% of the abdominal constrictions when evaluated against the writhing test at 10 mg kg(-1), intraperitoneal. It also caused dose-dependent inhibition in the same model, with a calculated ID(50) value and respective confidence interval of 10 (9-14) mg kg(-1), and was more potent than reference drugs. Administered orally, E(2) caused potent antinociceptive action, with a calculated ID(50) value of 35 (26-47) mg kg(-1). The fractions F(1) and F(2) obtained from E(2) were evaluated against the writhing test at 10 mg kg(-1), causing inhibitions of 41 and 88%, respectively. The most active fraction, F(2), presented ID(50) calculated value of 3 (2-4) mg kg(-1), being about 7-fold more active than the reference drugs (acetyl salicylic acid and acetaminophen). In the formalin test, F(2) inhibited both phases of pain (44%, first phase; 58%, second phase). However, in contrast to the results observed for E(2), it was not active against the hot-plate test. The phytochemical results showed that at least four main components are present in F(2), which show a positive reaction of terpenes with TLC spray reagents.

ChemiCal Composition and analgesiC aCtivity of the leaves and branChes ofThis paper describes the isolation of five phytoconstituents from Marlierea tomentosa. The triterpenes α-amyrin (1) and β-amyrin (2), and the flavonoids quercitrin (3) and isoquercetin (4), were isolated from the leaves. The branches afforded the triterpene arjunolic acid (5). The antinociceptive activity of crude extract, fractions and compound 5 were tested using the writhing and formalin tests in mice. The crude extract, some fractions, particularly dichloromethane and butanol (leaves), ethyl acetate (branches) and arjunolic acid (5) (81.2% inhibition) were more active against the writhing test than the two reference drugs, acetylsalicylic acid and indomethacin.